A Closer Look at RIPE’s Newest Qualifying Practice: Covers on Waste Lagoons

RIPE’s researchers continually work to expand the set of practices that would qualify for $100 per unit payment under the proposed RIPE100 program by collecting research that demonstrates the combined environmental value of climate-smart practices.

This month, we added the use of covers on waste lagoons (NRCS code 367) for swine and dairy animal feeding operations. Lagoon covers can reduce emissions and provide additional environmental benefits valued at over $840 per animal unit per year.

We found that farmers who implement lagoon covers reduce greenhouse gas emissions by around 2.2 metric tons per animal for a public value of $43 per acre. They also provide at least $780 per animal unit in air quality benefits. 

Review our methodology and sources in the charts below and access our current list of proposed qualifying practices here

Ecosystem Service Stack: Implementing Roofs and Covers* on a swine waste lagoon (367)

Ecosystem ServiceBenefit ($/Animal Unit/year)Methodology
Ammonia emissions reduction (human health benefits)$783A covered swine lagoon saves 9lbs of ammonia from storage-related loss per head of swine (“Managing Manure to Improve Air and Water Quality,” USDA ERS, 2005). Divided by 0.4 for animal unit conversion yields a value of 22.5lbs/AU. The public health cost of ammonia emissions in the United States is $48,565/ton NH3 (Heo et al. 2016), resulting in a per-animal unit benefit of $546.

In “Ammonia and greenhouse gas emissions from slurry storage – A review,” Kupper et al. (2020) determine that swine lagoon covers* tend to reduce ammonia emissions by an average of 71% compared to uncovered lagoons. The data suggests that covering lagoons reduces ammonia by 42 pounds/animal unit. Multiplied by $24.28/lb ammonia yields a public health value of $1,020/AU (Kupper et al. 2020).

The average of $546/AU/yr and $1,031/AU/yr equals $783/AU/yr.

*Cover types for which there was available ammonia data: lid (wood or concrete), tent covering, plastic film, plastic fabrics, expanded clay, expanded polystyrene, plastic tiles, peat, straw cover, and vegetable oil.

Methane Emissions Reduction
$62The average emissions from an uncovered swine waste lagoon total 31kg/m3/year. At 50 m3 of lagoon required per swine AU, the baseline emissions are 1,550kg methane/AU/year (Kupper et al., 2020). Kupper et al. (2020) determined that swine lagoon covers* reduce methane emissions by 8%, or 124 kg/AU/year. When converted to CO2e/AU and converted to metric tonnes, the reduction is 3.1 tonnes/AU. At a value of $20/tonne CO2e, the benefit is $62/AU.

*Cover types for which there was available methane data: lid (wood or concrete), plastic film, plastic fabrics, expanded clay, expanded polystyrene, plastic tiles, peat, straw cover, and vegetable oil.

Carbon Dioxide Emissions Reduction$.10The average carbon dioxide emissions from an uncovered swine waste lagoon are 2.7kg/m2/yr (Kupper et. al. 2020). At 21 m2 of lagoon per dairy AU, the baseline emissions are 56 kg/AU/year. Kupper et al. (2020) determined that swine lagoon covers* reduce carbon dioxide emissions by 9%, or 5kg CO2/AU/year. This converts to 0.005 tonnes/AU/year. At a value of $20/tonne, the benefit is $0.10/AU/year.
Total$844.10

*Cover types included in this methodology: Lid (wood or concrete), tent covering, plastic film, plastic fabrics, expanded clay, expanded polystyrene, plastic tiles, peat, straw cover, and vegetable oil.

Ecosystem Service Stack: Implementing Roofs and Covers* on a dairy waste lagoon (367)

Ecosystem ServiceBenefit ($/Animal Unit/year)Methodology
Ammonia emissions reduction (human health benefits)$915In “Ammonia and greenhouse gas emissions from slurry storage – A review,” Kupper et. al. 2020 find that storage covers* on dairy waste lagoons tend to reduce ammonia emissions by an average of 75%. The average ammonia emissions from a dairy waste lagoon total 43 kg/animal unit/year. A 75% reduction thus equals 71lbs/head/year. The public health cost of ammonia emissions in the United States is $48,565/ton NH3 (Heo et al. 2016), resulting in a per-animal unit benefit of $1,724.

In “Measurement of Atmospheric Ammonia, Methane, and Nitrous Oxide at a Concentrated Dairy Production Facility in Southern Idaho Using Open‐path Ftir Spectrometry,” Bjorneberg et. al, 2009 found that a waste lagoon on a dairy farm emitted 7.25kg of ammonia per day. When adjusted for an annual rate and divided by the herd size, emissions equal 3.7kg/head/year. At a 75% reduction rate from implementing a cover (Kupper et al., 2020), the emissions reduce by 4.46lbs/AU/yr, creating a benefit of $107/AU/yr.

The average of $1,724/AU/yr and $107/AU/yr equals $915/AU/yr.

*Cover types for which there was available ammonia data: lid (wood or concrete), tent covering, plastic film, plastic fabrics, expanded clay, plastic tiles, peat, straw cover, and vegetable oil.

Methane Emissions Reduction
$25Kupper et al. (2020) find that uncovered dairy lagoons emit 8.3 kg methane/m3/year. Assuming 46 m3/animal unit, methane emissions total 381 kg/animal unit/year. Assuming that a dairy lagoon cover* reduces methane emissions by 13% (Kupper et. al. 2020), emissions reductions total 50 kg/AU/year. Converting to tonnes of CO2e yields a value of 1.2 tonnes CO2e/AU/year. At $20/tonne CO2e, the value of implementing a cover is $25/AU/year.

*Cover types for which there was available methane data: lid (wood or concrete), plastic fabrics, expanded clay, straw cover, and vegetable oil.

Carbon Dioxide Emissions Reduction$4Kupper et. al. 2020 find that an uncovered dairy lagoon emits 58 kg/m2/year, which equals 2.26 tonnes CO2e/animal unit/year if assuming 39 m2 per animal unit. Assuming that a dairy lagoon cover* reduces CO2 emissions by 9% (Kupper et. al. 2020), the cover will reduce CO2 emissions by an average of 0.2 metric tonnes CO2 per AU per year when standardized. The benefit, at $20 per metric tonne, totals $4/AU per year.

*Cover types for which there was available CO2 data: plastic fabrics, expanded clay, straw cover, and vegetable oil.

Total$944

*Cover types included in this methodology: Lid (wood or concrete), tent covering, plastic film, plastic fabrics, expanded clay, expanded polystyrene, plastic tiles, peat, straw cover, and vegetable oil.